You Owe Me
by DemonSurfer
Summary: Dib owes Zim a favor, and now it's Zim's turn to collect.
1. Chapter 1

_**"It was a stupid idea."**_

"I know."

The Irken shifted slightly on his perch; PAK pressed painfully against the trunk of the tree. Sunlight was filtering through the leaves all around him, a shaft of it shining directly onto his closed eyelids. Only semi-conscious to begin with, he moaned softly as the light brought him the rest of the way awake. Without opening his eyes, his incredibly sensitive antennae could pick up the sound of birds chirping cheerfully, people calling to one another on the street, and the honking of car horns as the were trapped in morning traffic. In a general sense of the term, it seemed like a beautiful day.

Zim felt like shit.

_**"But that makes sense."**_

"Shut up…" he moaned, only a trace of tired aggression left in his voice. He leaned forward, finally giving up the vague possibility of going back to sleep and half-opening both eyes. His sight was blurry at best, only the biggest and most obvious details being visible. One gloved claw came up to rub at his poor eyes; the other stayed right where it was. After a moment he blinked blearily. His sight was still somewhat fuzzy, but at least close objects were reasonably clear. That made sense as well, seeing as the fake lenses had been in his eyes for over two days now without reprieve.

Zim sighed and let his eyes close again tiredly. The hand that had been rubbing at his eyes came up to gently finger the inflamed wound on the back of his neck, just to the left of the bone and right at the top of the spine. He hissed through clenched teeth as even that small touch sent burning pain through his body, almost causing him to loose his balance on the tree limb he had spent the night on.

_**"Come on, lazy. It's eight-sixteen; skool starts in fourteen minutes."**_

Zim wondered if jumping from higher up in the tree would kill him.

With another sigh he attempted to stand up on the mildly curved branch, one claw pressed firmly into the tree trunk to keep his balance. It was about the only part of him that wasn't shaking slightly as he finally got to his feet. The palm was replaced with a shoulder as Zim leaned against the tree for a brief rest. He wanted nothing more than to just sink to his knees and go back to sleep, no matter how uncomfortable sleeping in a tree was. He had a job to do, though, and a disguise to maintain. Besides, someone might come by and see him while he was asleep and defenseless. No, going to skool was his best option for now.

Leaving was less of a jump and more of a fall straight out of the tree. Zim lay face down for a moment, his face getting well acquainted with the local dirt population before his stunned mind could pull him to his feet. He swayed like a drunk and stumbled back slightly, PAK crashing against the trunk of the tree he had so recently vacated. He shook his head to try and clear it, blinking rapidly. The top compartment of his PAK opened up and he reached back to pull out a wig, the wig being of the same age as his lenses. He regarded the thing contemptuously for a moment, then put it on his head over his antennae.

Instantly his world dimmed. The Irken hadn't realized how much he had been relying on the information from his antennae until they were covered up. Hurriedly he snatched the wig off again, breathing a sigh of relief when his senses returned. He twirled the abused wig on one claw as he thought over the interesting problem this presented. He needed his wig for his human disguise, but with his antennae covered he was severely handicapped. He had enough handicaps to deal with at the moment.

_**"Poke some holes in it."**_

Zim stopped spinning the wig, glaring at the air in front and a little above him. "I could have come up with a solution on my own, thank you," he growled out, a little more aggression in his voice then had been there previously. Moving around had helped him regain a little energy. With a sharp claw he pierced the material twice, once for each appendage. He then put the wig back on his head, carefully threading his antennae through the holes. With his antennae lying flat no one would be able to tell them from the fake black hair of the wig.

The Irken got up off of the tree, catching himself before he fell over. He stood as still as possible for a few moments, military training allowing him to gain control over his body. When he walked out of the small park his tree was in, there was no trace of unsteadiness in his stride.

That still didn't mean that he wasn't dreading skool, though.

---

_"Dib, what are you doing?"_

_Zim stared at the human, suspicion lacing his voice. The Dib was acting weird, and it could be a plan of his to expose Zim as an alien. Zim wouldn't be fooled that easily, though. He kept his distance from the boy, squinting at him through the gloom of the filthy alley with disguised eyes. _

_Dib didn't answer him for at least a minute, which agitated Zim further. The Irken was opening his mouth to repeat the question, this time with insults and in a higher range of decibels, when Dib finally looked up at him. The human was pale, paler than his normal computer-bleached pale. He also looked extremely tired, like he hadn't even blinked in over a week. The bruised-looking flesh under his eyes only emphasized both of these. _

_"What am I doing? I'm not doing anything, Zim," Dib replied somewhat weakly, his voice cracking over the end of the sentence. "I'm just sitting in this alley." _

_One of Zim's antennae twitched slightly under the wig as the Irken took note of the change in Dib's voice. He walked a few paces nearer to Dib, stopping to continue his inspection of the human. _

_"You're lying," he said bluntly, watching for Dib's reaction. The corner of his mouth twitched in what could have been a smile, but otherwise he remained motionless, returning Zim's stare evenly. Now a little closer, Zim could see the human's eyes were glazed slightly. "What are you doing in this alley? Tell Zim!" he commanded._

_Dib sighed, dropping Zim's gaze in favor of the slightly damp asphalt he was sitting on. It had rained last night and the night before that. "Zim, if you really want to know, I'm here because I don't have the energy to move. That, and I feel that if I **do** move, I'll puke everywhere."_

_Zim's imaginary eyebrow rose._

_"The Dib is sick?"_

---

Skool. Loud, smelly, and overcrowded with inferior life forms.

Zim was beginning to regret freeing his antennae from his wig.

_**"Well, it was either this, or you stepping blindly out in front of a bus."**_

Zim didn't bother to reply this time. He watched from the sidewalk with distaste as hundreds of filthy human children poured out of the buses, flooding into the skool like they actually wanted to be there. They all talked to one another at the same time, creating a cacophony of pure noise that caused Zim's antennae to press further down into his wig to block it out. That didn't help much, the delicate organs being extremely sensitive anyway.

A wave of dizziness washed over him suddenly; most likely brought on by the overwhelming amount of information his brain was receiving. The Irken had to stop walking before he lost his balance and fell over onto the sidewalk, something that would have been completely undignified for an Invader. After a moment or two the sensation passed, though it left its mark as a slightly nauseous feeling in the pit of his squeedlyspooch. He didn't doubt for a moment that the feeling would get worse as the day progressed.

_**"Dib, coming up behind you in a sad imitation of ninja stealth. He apparently intends to jump you."**_

Zim sighed, glaring blindly at the air in front of him. He suddenly directed that glare over his shoulder after counting to ten in his head, the movement causing the wound on his neck to send out another jagged wave of pain. His sight going momentarily fuzzy from another brain overload, Zim didn't let his expression reveal anything to Dib.

The human was standing behind him as reported, his arms crossed and a cocky grin on his pale face. Behind him was his sister, Gaz, her nose buried in a handheld game as always. Zim didn't waste any of his attention on her, focusing his glare solely on Dib. If the human thought that Zim was in the mood for their usual "game", he was about to be sorely disappointed.

Wounded, too, if that could be arranged.

"Dib." A single word, but full of so much hatred. It was a warning: Don't mess with me, I'm not in the mood. Unfortunately, Dib was especially thick-headed when it came to anything Zim said.

"Zim." The cocky grin grew wider, as if Dib had just said the secret word and won a million dollars. "I know you've got some kind of plan to destroy Earth, and I'm going to figure out what it is. You might as well give up and make it easy on yourself by telling me what it is right now." Zim squinted at him as if he were actually considering the human's proposition.

"Gee Dib, I'd love to," he started, rubbing his chin thoughtfully. "But that would mean giving up the chance to destroy you, along with betraying my race and all that jazz. So I'm sorry, you're just going to have to wait until you're destroyed to see what my plan is." Another bolt of pain shot through the Irken's neck as he waved his hand in the air nonchalantly, and he had to resist flinching.

_**"If your plan doesn't destroy you first."**_

* * *

A/N: Ooh, mysterious. Kudos to whoever can figure out who is speaking **_like this_**. The first, and hardest, hint I can give you that doesn't make it blatently obvious(to me) is that Zim is the only one that can hear the speaker.

This will be a short fic, 3 or four chapters long.


	2. Chapter 2

Zim glared at Dib. Dib glared at Zim. Gaz walked past them both, unnoticed, sneering at their childish display. It was a stalemate and a competition; who would look away first? Who was weaker?

The warning bell rang.

Both boys blinked at the same time, looking as if they had just come out of a trance. Zim recovered first, flashing his zipper-like teeth at Dib in a mocking grin. He then turned and fled for the relative safety of the skool building, weaving between the crowds of human children until he was safely in the hall. Only when he was leaning against the lockers far from the door did he allow himself to let out the breath he had been holding. The kids would slow Dib down enough that he would have a hard time following Zim.

****

"Feeling threatened?"

"Hardly," Zim muttered, pushing himself off of the lockers and wincing. The run had made the nauseous feeling in his squeedlyspooch worse, and his muscles were trembling slightly again. He held as still as possible until he had the tremors under control again. He glared at the air in front of him as he stalked to his classroom.

Zim had just sat down at his desk when the second bell rang, its shrill cry causing his antennae to press even closer to his head. A moment later and Dib slid into the room, glaring sullenly at Zim as he passed the Irken on the way to his desk. Zim returned the glare, even though he was developing a headache from scowling so much. A flicker of black out of the corner of his eye attracted his attention, and he turned in time to see Ms. Bitters appear from behind her desk. She wore her own scowl, clearly advertising her hatred of all who were present and of life in general.

****

"You know, I wonder what she has back there."

One of Zim's antennae cocked slightly in interest. "Probably some sort of torture chamber," he said with a slight smirk. Ms. Bitters began speaking, starting with her usual condemnation of the collective student body speech.

****

"Maybe. Or a secret disco lair."

"What? Disco lair?"

The sound of a throat being cleared attracted Zim's attention, and he glanced over his shoulder to see Zita glaring at him. When they made eye contact she muttered something about Zim being crazy. Zim snorted and turned around again so that he was facing forward, propping his chin in one hand as he tuned into Ms. Bitters' lesson on how America was discovered by some guy named Kris-No-Fur Clown-Bus in 1429. He could almost feel his brain turning to mush after ten seconds.

Zim was staring blankly at the board with slightly glazed eyes when something having at least one corner hit him. It smacked lightly into the side of his head right above his hand and fell on the desk. The thing turned out to be a folded piece of paper, and from the angle it had been thrown, the sender was most likely Dib. Zim glanced over at the human, who was staring at him intently. He kept a suspicious blurry glare on Dib until the note was unfolded, at which point he glanced down to read it.

****

**Zim-**

**Whatever you're planning, I'm going to stop it. Give up now.**

Beneath those two simple lines was a bad stick figure drawing of Zim. The scribble depicted the alien on an autopsy table, a giant scapel hovering menacingly over his body and his guts splayed everywhere. A corner of Zim's mouth twitched. Lovely.

Reaching into his PAK, Zim fished around for a while before pulling out a half-chewed pencil he had rescued from Gir at some distant point in time. He quickly added to the note, writing a phrase that was rude in both Irken and English. He also drew a Dib stick-figure where the scapel was stabbing into its head with plenty of blood, courtesy of random pencil strokes. Zim swiftly folded the note back up along its original creases and flung it expertly at Dib's head. It hit him squarely in the ear and stayed there, causing Zim to snicker into his hand as Dib jumped and yanked the paper out of his ear.

Even feeling like shit, there were still some perks in Zim's day.

---

The human sighed, looking back at the ground. "Yes Zim, the Dib is sick."

Zim decided to grace the situation with a loud and, from his point of view, appropriately mocking laugh. Complete with a pointing finger at Dib. The laugh continued on for at least thirty seconds before he inhaled at the wrong moment and dissolved into a fit of coughing. When he had sufficiently recovered, he looked back at Dib. A smirk tugged at one corner of his mouth as he regarded the human smugly.

Dib raised an eyebrow as the Irken stared at him without saying anything, only grinning predatorily. Finally the boy couldn't take it. He struggled up off of the brick wall with a cough. "What?" He asked with a glare.

"You're sick," was Zim's smug reply. Dib gave him a flat look.

"Um, yeah Zim. I think I already said that." The Irken's expression didn't change. He walked forward until he was kneeling in Dib's face, careful not to touch the still-damp ground. He flashed Dib a predator's smile, filled with teeth.

"No Dib, you don't understand. You're sick. That means you're weak, that you're vulnerable. Right in front of your enemy." He said.

It took Dib a few minutes to realize what Zim had said. When he did, his eyes widened for a moment before his head dropped. He slumped back against the wall, causing the Irken to cock his head in confusion.

"I hate you," he grumbled, coughing again and glaring up at the alien. "I give up."

Zim was stumped. Dib never gave up, **never** just quit. He had to be planning something, although Zim wasn't sure what he could be planning in the sorry state he appeared to be in. That is, if he was telling the truth about being sick in the first place. Cautiously the Irken inched a little bit closer, squinting at Dib as though he were a museum specimen.

"You're up to something…How does Zim know you're not lying about being sick?" He said suspiciously. Dib shot him an utterly flat look.

"Zim, do I **look** well to you?" He asked bluntly. Zim took a moment to reassess the human's condition. No, he looked honestly sick. The Irken wasn't convinced, though, and Dib picked up on that. He sighed and leaned his head back against the wall.

"Look Zim, I'll tell you something. I don't get sick often, but when I do, I get really sick. So there's not a lot I can do right now," Dib said, looking at Zim out of the corner of his eye. Zim continued to scowl at him, still not fully convinced.

In the slight pause that followed, a peal of thunder echoed across the sky.

---

Something hit Zim.

Normally the Irken wouldn't have even cared. Indeed, in the zoned out state that he was in, he probably wouldn't have noticed if a textbook was thrown at him until it was ten minutes after the fact. The difference this time was that whatever hit him, hit him on the back of the neck. Though it didn't have much mass, the place it hit was right above the injury hidden by his Invader uniform's collar.

The reaction was immediate. The Irken let out a yelp, jaw clenching in an attempt to prevent any further noise. He curled inward, one hand coming up to hover above the wound. His head swam from the pain that shot through it from the small touch, and he broke out in a cold sweat. For a moment Zim thought he would pass out in the middle of class. Then the moment passed and the Invader, still panting slightly, turned his narrowed eyes to whatever had hit him.

It was the note, folded into a deadly triangle and sitting innocently on the floor. Zim didn't even bother picking it up, instead glaring across the room as hatefully as he could. He could see Dib flinch visibly from the force of the glare, although the human tried to return it anyway. After a few second, though, he dropped his eyes.

****

"You're being stared at."

Zim blinked and looked around. Over half of the class was staring at him, most with the expression that meant that they considered this new act just another form of his insanity. Like the good distressed Irken he was, Zim's response to this new attention was to hiss at them. As this was something they were used to, as opposed to the weird twitching he had just done, the satisfied class promptly went back to ignoring Zim. Zim glared at them for a few more moments before turning his attention back to Dib.

The human was trying his hardest to disappear into his seat, rightly afraid of the Irken's wrath. Zim was pretty sure Dib had no idea what had just happened, but knew that it had pissed Zim off. And it had.

The bell for lunch rang shrilly in the silence.

---

One more chapter, then we're through.


End file.
